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United States Department of Agriculture

Agricultural Research Service

Rodney T. Venterea (Rod)

Soil Scientist

Lead Scientist Soil & Water Mgmt Research Unit

 

Adjunct Professor, Dept. of Soil, Water & Climate, University of Minnesota

Graduate Faculty, Land and Atmospheric Science Program

Technical Editor and Science Communications Editor, Journal of Environmental Quality

 

PhD Soil Science, University of California Davis 2000

MS Civil Engineering, University of Massachusetts Lowell 1991

AB Dartmouth College 1983

Research Program

Publications

Google Scholar Citations 

Recent Findings and Contributions

Resources for chamber measurement

Our research in recent news reports

 

Research Program: We study the biogeochemistry of elements that impact both agricultural productivity and environmental quality. Much of our work focuses on the reactive nitrogen (N) compounds - including nitrous oxide, nitric oxide, nitrate, nitrite and ammonia - each of which can have ecological impacts at local, regional and/or global scales when their concentrations become elevated above naturally occurring levels. We work mainly in agricultural ecosystems, but also in forest and other systems. Our work aims to better quantify, understand and predict the biochemical production and transformation of reactive N species within the soil and their physical transport to the broader environment using lab, field, and modeling techniques. We are also interested in the biogeochemistry of carbon and phosphorus.Our parallel objective is to develop and test improved management systems and treatment technologies that minimize nutrient-based impacts while maintaining agricultural production capacity and other ecological services.

 

Recent Findings and Contributions

Identification of overlooked controls on soil nitrous oxide production.  Nitrous oxide (N2O) is a potent greenhouse gas and ozone depleting chemical that is emitted to the atmosphere following application of nitrogen fertilizers or deposition of animal wastes to soil.  Improved understanding of the processes regulating N2O production in soil is critical to better estimation and mitigation of N2O emissions. This study was the first to find that differences in the capacity of soils to adsorb N fertilizer in the form of ammonium onto their surfaces is a key factor controlling differences in rates of N2O production.  We also found that decreased surface ammonium sorption inhibited a certain class of soil bacteria which can act to reduce N2O production. These results will be useful to scientists and land managers interested in developing improved N2O emissions models, and in developing management practices to reduce N2O emissions.  Publication: Venterea R.T., T.J. Clough, J.A. Coulter and F. Breuillin-Sessoms. 2015. Ammonium sorption and ammonia inhibition of nitrite-oxidizing bacteria explain contrasting soil N2O production. Scientific Reports, 5, Article number: 12153, doi:10.1038/srep12153.

 

Delayed timing of fertilizer application may increase nitrous oxide emissions.   Modification  of fertilizer management practices to reduce emissions of N2O has been identified as a key strategy for reducing the greenhouse gas footprint of agricultural cropping systems. Altering the timing of N fertilizer application is frequently mentioned as a potentially effective practice for reducing all forms of N loss from fertilized soil.  However, in this two year field study, we found that application of N fertilizer later in the growing season did not necessarily reduce, but actually increased, N2O emissions. This resulted from variation in rainfall and soil moisture which are not easily predicted or managed in rainfed systems.  These results provide important information for developing effective practices to reduce soil N2O emissions. Publication: Venterea, R.T. and J.A. Coulter. 2015. Split application of urea does not decrease and may increase N2O emissions in rainfed corn. Agronomy Journal, 107. doi:10.2134/agronj14.041.

 

Soil nitrite dynamics explain fertilizer management effects on nitrous oxide emissions. It is typically assumed that the dependence of nitrous oxide emissions on soil nitrogen availability is best quantified in terms of ammonium and/or nitrate concentrations.  In contrast, nitrite (NO2-) is seldom measured separately from nitrate despite its role as a central substrate in nitrous oxide production.  We examined the effects of three fertilizer sources and two placement methods on nitrous oxide in corn over two growing seasons.  Cumulative nitrous oxide emissions were well-correlated with nitrite intensity but not with nitrate or ammonium intensity.  By itself, nitrite intensity explained more than 44% of the overall variance in cumulative nitrous oxide emissions. These results show that practices which reduce nitrite accumulation have the potential to also reduce nitrous oxide emissions, and that separate consideration of nitrite and nitrate dynamics can provide more insight than their combined dynamics as typically quantified. Publication: Maharjan, B. and R.T. Venterea. 2013. Nitrite intensity explains N management effects on N2O emissions in maize. Soil Biology and Biochemistry. 66:229-238

 

International guidelines for improved nitrous oxide emissions measurements.  Soil nitrous oxide emissions are in many cases the largest component of the greenhouse gas impact of agricultural systems.  However, measurements of nitrous oxide fluxes are highly sensitive to the methods deployed and there is currently wide variation in methodologies.  Working as part of an international team of experts from 10 countries, we developed a set of peer-reviewed methods guidelines that are being distributed internationally via the website of the Global Research Alliance.  These guidelines will be useful to scientists and technicians from around the world engaged in research related to agricultural nitrous oxide emissions and will result in more accurate and precise measurement of nitrous oxide emissions from croplands and grazing lands. Publications:  Venterea, R.T., Parkin, T.B., Cardebas, L., Petersen, S.O., Petersen, A.R. 2012. Data analysis considerations (Chapter 6). In: Deklein, C., Harvey, M., editors. Nitrous Oxide Chamber Methodology Guidelines. Global Research Alliance on Agricultural Greenhouse Gas Emissions.

 

 

 

Resources for chamber measurement

*Chamber Error Assessment Tool (CEAT):

-> Excel file

-> Related article: Venterea et al (2009)

*Chamber Bias Correction (CBC) Method:

->Article:Venterea (2010)

->Simplified calculations (Excel file)

->Related articles: Venterea (2013), Venterea & Parkin (2012) Venterea et al (2009), Venterea & Baker (2008)

*Detection Limit Estimation:

->Article:Parkin et al (2012)

->Supplement (step-by-step instructions)

->Simplified calculations (Excel file) 

*Protocols:

->GRACEnet Chamber Measurement Protocol (Parkin & Venterea, 2010)

->GRA Nitrous Oxide Methodology Guidelines (Link to complete collection, Eds. de Klein & Harvey)

->Chapter 6. Data Analysis Considerations (PDF)

*Chamber design:

->Stainless steel chambers fabricated from steam pans

 

Recent News

* Agricultural N2O emissions may be underestimated due to stream emissions

* Conservation ag may not reap hoped for global yield gains

*Agricultural Research Magazine: Nitrite's Role in Soil N2O Emissions

 

 

 

 

 


Last Modified: 7/28/2015
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